Nyctomys sumichrasti (Saussure, 1860)

Species Identification

Sumichrast's vesper rat, Nyctomys sumichrasti, is a relatively small rat.

Body Length

Adult body length (not including the tail) measures 10 to 13 cm (3.9 to 5.1 in), and the tail is only slightly shorter than the body.

Weight

Males and females are similar in size, with both sexes weighing between 220 and 245 g (7.8 to 8.6 oz).

Pelage Coloration

It is one of the more brightly colored rat species, with a reddish or orange back and creamy to white underparts.

Fur Distribution

It has a thick pelt of soft fur that covers the full length of its tail, and is only absent on the soles of the feet.

Head Features

Its eyes are relatively large and surrounded by a narrow ring of black hair, while its whiskers are long and its ears are small.

Climbing Adaptations

To help with climbing, its claws are compressed and curved, and the first toe on each foot is shaped like a thumb.

Geographic Range

Sumichrast's vesper rat ranges from southern Jalisco and Veracruz in Mexico through most of Central America (excluding the Yucatan Peninsula) as far east as central Panama.

Habitat and Elevation

Across this range, it lives in evergreen and semi-deciduous forests at elevations from sea level up to 1,600 m (5,250 ft).

Subspecies

Nine subspecies are currently recognized: N. s. sumichrasti from southern Veracruz, Mexico; N. s. colimensis from Jalisco to Oaxaca, Mexico; N. s. costaricensis from southern Costa Rica; N. s. decolorus from southern Belize and eastern Guatemala to Honduras; N. s. florencei from southern Honduras and western Nicaragua; N. s. nitellinus from eastern Costa Rica to central Panama; N. s. pallidulus from southern Tabasco and western Chiapas, Mexico; N. s. salvini from eastern Chiapas, Mexico and southern Guatemala; and N. s. venustulus from eastern Nicaragua.

Mating Period

Mating takes place throughout the year.

Gestation and Litter Size

Gestation lasts from 30 to 38 days, after which one to three young are born.

Nesting Behavior

Both parents build the nest where the young are reared, though the male usually stays outside the nest for the first seven days after birth.

Newborn Size

Newborn young are about 8 cm (3.1 in) long and weigh 4.5 g (0.16 oz).

Juvenile Development

They are born blind, only partially covered in fur, and remain attached to the mother's teats for most of their first two weeks, but are able to crawl starting from two days of age.

Weaning and Eye Opening

They are weaned at around three weeks old, and their eyes open between fifteen and eighteen days after birth.

Sexual Maturity and Lifespan

They reach sexual maturity at around 75 days of age, and have been recorded living up to five years in captivity.